The
project presentation
The operation experience from now shown that during of NPS operation can
appear important safety problems especially due to degradation by corrosion of
its constructive elements. To avoid the economic penalties as well to diminish
the pollution risk of environment, it follows the increasing of operation
period in safety conditions of structural components, which require the
knowledge and understanding of several corrosion mechanisms which can conduct
at their degradation, that should be possible the establishment of generating
causes and the identification of those solutions that should diminish or even
prevent them.
The present project has the principal scope the enlarged research and
development infrastructure of „LADICON” laboratory, realized in SCN Piteşti in the
framework of the Ministry of Education and Research Program “Research of
Excellence” Modulus IV 2006-2008
Short presentation of
achievements in specified Scientific and Technique field at national and international
level
Knowing that corrosion mechanisms implied in the degradation processes
of several metals and alloys essentially depend on physical-chemical conditions
of existing corrosive medium, the problem of metals corrosion preoccupied both
the scientifically world and the producers and users of metallic materials.
Due to permanent presence of a potential danger, a great importance was
given to corrosion evaluation and prevention in energetic field, implicitly
also to nuclear energetic, metallurgic and oil field. The main activities have
as aim the development of investigation techniques and methods of structural
materials corrosion, methods of chemical control of environment as well as the
construction of data bank that permit the modeling of several corrosion types
characteristic to different systems material/medium and the prediction of safe
exploitation life of several structural components.
In addition, in world are some permanent preoccupations referring to the
study of new methods to prevent the corrosion processes or to reduce their
negative effects, but and some possibilities of their applications especially
in the nuclear field.
In our country, even before the putting into service of nuclear power
station, the corrosion processes specific to metallic components surfaces of
corresponding cooling circuits were been approached. Actually, the experimental
study of several degradation mechanisms that can affect the components of two
circuits of NPS in normal and abnormal working conditions became a prioritary
direction of research activity, especially after the putting into service of
Unit 2 of NPS Cernavodă.
The research in this field, carried out by Institute for Nuclear
Research Piteşti, follow the continuation of the tradition in the field of
experimental studies of physical-chemical processes associated with the
corrosion phenomena in the aim to identify the mechanisms of corrosion
degradation and the identification of those physical-chemical methods that
should diminish or prevent them.
The research activity carried out
along many years, conducted at the obtaining of the significant results
referring to the characterization and the prediction of behavior at uniform
corrosion and some localized corrosion types of several structural materials
used in two circuits of NPP function of materials conditions(composition,
chemical treatment, surface state), environment conditions (pH, presence of
some chemical contaminants, of some dissolved gases) and the testing parameters
(temperature, pressure, flowing regime, thermal flux and the radiation field).
In the frame of one agreement with Cernavoda NPP, some corrosion analysis and
examinations carried out on the samples exposed in some autoclaves in the
primary circuit of CANDU reactor after several operation periods to evaluate
the integrity state of the structural components of the primary circuit. The
results of these corrosion analyses were been included in a data basis. Such
corrosion analysis were been executed in the aim to put in operation the nuclear
station, to verify the passivity state of the primary circuit as well as after
its several operation periods.
In the frame of the Research Project coordinated by IAEA-Vienna
(2000-2005) ”Processing Technologies and Diagnosis Data of Water Chemistry and
Corrosion Control in Nuclear Installations” was been developed an informational
system of the chemical control of environment and of corrosion in the primary
circuit of CANDU nuclear station.
The acquisition and processing of the corrosion data assure quick and
efficient information referring to:
- water chemistry (normal
operation procedures and improving conditions);
- corrosion evaluation
(the determination of corrosion rates, of deposit and respectively the
delivered corrosion products and referring to the oxides films);
- the apparition and
evolution of some localized accelerated corrosion processes and the modeling of
some oxidation phenomena.
Being known that the world tendency in nuclear field is the increasing
of burn up degree of nuclear fuel, SCN Piteşti is partner in the Research
Project Coordinated by IAEA-Vienna (2006-2010): “The optimization of Water
Chemistry in the Aim to Assure a High Performance to High Burning Fuels from
Nuclear Reactors”.
The results of the research works carried out in “Corrosion,
Decontamination and Water Chemistry Laboratory” from the Institute for Nuclear
Research permitted the development of expertise activity in the evaluation of
corrosion of some corroded samples, the identification of the causes of an
advanced corrosion and the finding of some adequate solutions to diminish the
respective corrosion processes in the frame of the “Analysis and Diagnosis
Laboratory of the Corroded Metallic Components from the Nuclear Installations”.
